Changes between Version 3 and Version 4 of TBR/User/BenGras

Timestamp:

05/06/15 11:29:29 (9 years ago)

Author:

Ben Gras

Comment:

flesh out api with example pin number definitions and example usage and file names and status codes

TBR/User/BenGras

@@ -2 +2 @@
 
 {{{#!c
+
+/* <rtems/gpio.h> */
+
 /* a configured GPIO pin handle. this is filled in by rtems_gpio_configure_pin_*
  * and can then be passed to other api functions.
@@ -15 +18 @@
  * the gpio_pin struct is then filled in and can be passed to other functions.
  */
-rtems_gpio_configure_pin_digital_out(&gpio_pin_handle, pin_number);
+int rtems_gpio_configure_pin_digital_out(&gpio_pin_handle, pin_number);
 
 /* for a digital_out pin, set it to logical high */
-rtems_gpio_digital_set(&gpio_pin_handle);
+int rtems_gpio_digital_set(&gpio_pin_handle);
 
 /* for a digital_out pin, set it to logical low */
-rtems_gpio_digital_clear(&gpio_pin_handle);
+int rtems_gpio_digital_clear(&gpio_pin_handle);
 
 /* a currently configured pin is to be released and made unused, allowing repurposing. */
-rtems_gpio_release_pin(&gpio_pin_handle);
+int rtems_gpio_release_pin(&gpio_pin_handle);
+
+/* returned error codes */
+#define GPIO_SUCCESSFUL        0 /* operation OK */
+#define GPIO_UNKNOWN_PIN       1 /* pin not known by bsp */
+#define GPIO_UNCONFIGURED_PIN  2 /* pin not configured with rtems_gpio_configure_* */
+#define GPIO_MISCONFIGURED_PIN 3 /* pin configuration doesn't match operation */
+
+/* <libcpu/am335x.h> */
+
+/* gpio pin definitions for the AM335X SOC */
+#define AM335X_V9     63  /* GPIO1[31], SOC pin  V9 */
+#define AM335X_V15    53  /* GPIO1[21], SOC pin V15 */
+#define AM335X_U15    86  /* GPIO2[22], SOC pin U15 */
+#define AM335X_T15    87  /* GPIO2[23], SOC pin T15 */
+#define AM335X_V16    88  /* GPIO2[24], SOC pin V16 */
+
+/* <bsp/beagleboneblack.h> */
+
+/* gpio pin definitions - same as above but with names
+ * indicating how they are wired on the Beaglebone Black board
+ */
+#define BBB_P8_20 71  63  /* GPIO1[31], BBB P8 header pin 20 */
+#define BBB_LED_USR0  53  /* GPIO1[21], BBB USR0 LED */
+#define BBB_LED_USR1  86  /* GPIO2[22], BBB USR1 LED */
+#define BBB_LED_USR2  87  /* GPIO2[23], BBB USR2 LED */
+#define BBB_LED_USR3  88  /* GPIO2[24], BBB USR3 LED */
+
+/* example usage */
+
+#include <rtems/gpio.h>
+
+struct gpio_pin_handle led_usr0_handle; /* opaque to the user */
+
+if(rtems_gpio_configure_pin_digital_out(&handle, led_usr0_handle) == GPIO_SUCCESS) {
+    rtems_gpio_digital_set(&led_usr0_handle);
+    rtems_gpio_release_pin(&led_usr0_handle);
+}
+
 }}}
+